Tank sender & possible fuel problem
It had been awhile since I started my '66, and the gas level had gotten so low that I didn't want to deal with trying to run it with the old gas in the tank. So I decided to just dilute it and put at least 10 gallons in it. It actually ran OK for a few minutes, but died and I couldn't get it started. I have a pressure gauge on the fuel line at the carb; it didn't move when I cranked the engine. So I figured the filter between the tank and the electric pump was plugged, even though I have an SS tank, so no rusting issues. I pulled the line from the tank off the filter and drained a bit of gas into a jar, shown in the photo. More about that in a bit.
I only got a small stream of fuel out the tube when I did that, so I wondered if the screen on the pickup was plugged in the tank. I drained the tank and pulled the sender. The screen was clean, but I noticed that it slid back and forth on the pickup tube. It could slide down far enough so that the end hit the end of the screen, blocking the pickup. The end around the tube looked like there might have been some kind of clamp around it at one point, so I put a spring tubing clamp on it to keep it from moving and put the sender back in the tank. I'm reworking the tubing to the tank, so I haven't been able to see if it fixed the problem.
Back to the test sample. I also poured a little from a new can of the same gas I put in the Mustang into another jar. You shouldn't have any trouble telling which is which in the photo. At the time I figured the gas in the tank was bad, but I noticed yesterday that the "new" gas had started to turn yellow. I then remembered that ethanol absorbs (perhaps not the right word) water, so maybe 10% ethanol gas turns yellow when exposed to air just like brake fluid does. I may just put the old gas back in the tank. I may filter it first, although I didn't see any evidence of sediment.